An optical transceiver is useful in applications, where power delivery and data transmission via electrical wires is problematic, in particular due to size restrictions of the power delivery and data transmission paths. Although the present invention is not limited to a use in medical applications, the present invention will be described herein with respect to medical applications.
In the medical field, there is a clear and ongoing trend to replace conventional surgical procedures with minimally invasive interventions. Reduced trauma, shorter hospital stay and reduced costs are the most important drivers of the adoption of minimally invasive techniques. To enable further innovation in medical instrumentation—thus enabling more advanced and more challenging minimally invasive interventions—there is a need to integrate miniature sensors for in-body imaging and physiological measurement in instruments like catheters and guidewires. The integration of sensors in the tip of such instruments implies the need for wires that can deliver power to the distal tip of the medical device and transmit data from the distal tip back to the proximal end of the medical device.
Data and power delivery to the tip of long and thin devices such as catheters or guidewires for imaging, sensing, sensitizing or even ablation can be challenging. Including, on top of that, high data rate return channel from the distal to the proximal end is even more problematic. This is due to several reasons.
Firstly, the combination of small cross-section (i.e. small diameter), necessary for the medical intervention, combined with the long length of a guidewire or catheter does severely limit the total number of electrical wires that can be integrated in such an instrument.
Secondly, the integration of multiple electrical wires compromises the flexibility of the instrument, while flexibility is a key property of this type of instruments.
Thirdly, for high data rate, such as e.g. required for an ultrasound transducer at the tip or for sensitive measurements, one often requires coaxial cables which need even more space compared to single-core wires.
Fourthly, instruments with electrical wires typically are not compatible with the use of magnetic resonance imaging due to resonances in/of the electric wiring leading to electromagnetic interference in the connected electronics and also possibly leading to tissue heating. And furthermore, thin electrical cables typically cannot support a relatively high amount of power for use at the distal end of the catheter.
Also, because of their disposable use, catheters and guidewires must be manufactured in a relatively simple and cost-effective way.
WO 2014/072891 A1 describes an optical transceiver which receives optical energy from a remote laser light source and converts the optical energy into electrical energy for powering the optical converter circuit of the transceiver. To this end, the optical transceiver comprises an optoelectronic device in form of a light emitting diode (LED). The optical converter circuit can have an electronic appliance which generates data. While this known optical transceiver is effective in providing sufficient power delivery capability to actuate an ultrasound catheter as an electronic appliance, because the optoelectronic device has a large surface area necessary to achieve the necessary power output, the large surface area of the optoelectronic device limits the bandwidth and, hence, the data rate of data transmission in the return path from the transceiver to the proximal end. For this reason, it is further proposed there to use a separate optoelectronic device, in particular a vertical cavity surface emitting laser (VCSEL) for data transmission in the return path from the distal end to the proximal end. However, a separate optoelectronic device for data transmission and a separate optoelectronic device for energy harvesting add significant complexity to both the electronic and optical part of the interventional instrument using the optical transceiver. A smaller LED used as the optoelectronic device would increase the bandwidth of data transmission, but stray capacitance and edge effects can spoil the situation, and the photovoltaic conversion efficiency of the LED is reduced.
Thus, the problem is that the optical transceiver either cannot deliver high bandwidth with a single LED only, or is less effective in photovoltaic conversion, or is complex due to the extra VCSEL and the associated cost, manufacturing and alignment problems.
Therefore, there is a need for an improved optical transceiver which retains the capability of achieving sufficient conversion power output, but increases the bandwidth of data transmission in the return path.